Tissue shaping device

ABSTRACT

In one embodiment, the present invention relates to a tissue shaping device adapted to be disposed in a vessel near a patient&#39;s heart to reshape the patient&#39;s heart. Such tissue shaping device can include an expandable proximal anchor; a proximal anchor lock adapted to lock the proximal anchor in an expanded configuration; an expandable distal anchor; a distal anchor lock adapted to lock the distal anchor in an expanded configuration; and a connector disposed between the proximal anchor and the distal anchor, the connector having a substantially non-circular cross-section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/907,907, filed Oct. 19, 2010, now U.S. Pat. No. 8,974,525; whichapplication is a continuation of U.S. application Ser. No. 12/060,781,filed Apr. 1, 2008, now U.S. Pat. No. 7,828,842; which application is acontinuation of U.S. application Ser. No. 11/275,630, filed Jan. 19,2006, now U.S. Pat. No. 7,351,260; which application is acontinuation-in-part of U.S. application Ser. No. 11/132,786, filed May18, 2005, now abandoned. Each of these applications is incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

This invention relates generally to devices and methods for shapingtissue by deploying one or more devices in body lumens adjacent to thetissue. One particular application of the invention relates to atreatment for mitral valve regurgitation through deployment of a tissueshaping device in the patient's coronary sinus or great cardiac vein.

The mitral valve is a portion of the heart that is located between thechambers of the left atrium and the left ventricle. When the leftventricle contracts to pump blood throughout the body, the mitral valvecloses to prevent the blood being pumped back into the left atrium. Insome patients, whether due to genetic malformation, disease or injury,the mitral valve fails to close properly causing a condition known asregurgitation, whereby blood is pumped into the atrium upon eachcontraction of the heart muscle. Regurgitation is a serious, oftenrapidly deteriorating, condition that reduces circulatory efficiency andmust be corrected.

Two of the more common techniques for restoring the function of adamaged mitral valve are to surgically replace the valve with amechanical valve or to suture a flexible ring around the valve tosupport it. Each of these procedures is highly invasive because accessto the heart is obtained through an opening in the patient's chest.Patients with mitral valve regurgitation are often relatively frailthereby increasing the risks associated with such an operation.

One less invasive approach for aiding the closure of the mitral valveinvolves the placement of a tissue shaping device in the cardiac sinus,a vessel that passes adjacent the mitral valve annulus. (As used herein,“coronary sinus” refers to not only the coronary sinus itself, but alsoto the venous system associated with the coronary sinus, including thegreat cardiac vein.) The tissue shaping device is designed to reshapethe vessel and surrounding valve tissue to reshape the valve annulus andother components, thereby promoting valve leaflet coaptation. Thistechnique has the advantage over other methods of mitral valve repairbecause it can be performed percutaneously without opening the chestwall. Examples of such devices are shown in U.S. application Ser. No.10/142,637, “Body Lumen Device Anchor, Device and Assembly” filed May 8,2002; U.S. application Ser. No. 10/331,143, “System and Method to Effectthe Mitral Valve Annulus of a Heart” filed Dec. 26, 2002; U.S.application Ser. No. 10/429,172, “Device and Method for Modifying theShape of a Body Organ,” filed May 2, 2003; and U.S. application Ser. No.10/742,600 filed Dec. 19, 2003.

SUMMARY OF THE INVENTION

Tissue shaping devices can encounter material stress while in storage,during deployment and after implant. Repeated stress can lead tomaterial fatigue and breakage. The present invention provides a tissueshaping device with improved stress response characteristics.

One aspect of the invention provides a tissue shaping device adapted tobe disposed in a vessel near a patient's heart to reshape the patient'sheart. The tissue shaping device has an expandable proximal anchor; aproximal anchor lock adapted to lock the proximal anchor in an expandedconfiguration; an expandable distal anchor; a distal anchor lock adaptedto lock the distal anchor in an expanded configuration; and a connectordisposed between the proximal anchor and the distal anchor, with theconnector having a substantially non-circular cross-section, such as asubstantially rectangular or substantially oval cross-section.

In some embodiments, the distal anchor lock includes a bend in theconnector and, optionally, a compliant element adjacent the bend in theconnector, with at least the compliant element being adapted to changeshape during a distal anchor locking operation. In some embodiments thedistal anchor lock has an anchor lock element adapted to move withrespect to the connector as the distal anchor expands.

In some embodiments, the connector is a first connector, and the devicealso has a second connector extending between the proximal and distalanchors. The distal anchor lock may make up at least part of the wireelement. The second connector can be adapted to provide fatigueresistance.

In some embodiments, the distal anchor has a crimp and a wire elementextending from the crimp, the wire element having a strain reliefportion extending distal of the crimp to form a bend extendingsubstantially below a plane defined by the crimp. The distal anchor wireelement may also have a vessel engagement portion extending proximallyfrom the strain relief portion and away from the crimp and a lockportion extending from the vessel engagement portion to form part of thedistal lock.

In further embodiments, the proximal anchor can include a crimp and awire element extending from the crimp, with the wire element having astrain relief portion extending distal of the crimp to form a bendextending substantially below a plane defined by the crimp. The proximalanchor wire element further may also have a vessel engagement portionextending proximally from the strain relief portion and away from thecrimp and a lock portion extending from the vessel engagement portionand forming part of the proximal lock.

Another aspect of the invention provides a tissue shaping device adaptedto be disposed in a vessel near a patient's heart to reshape thepatient's heart. The tissue shaping device may include an expandableproximal anchor, with the proximal anchor having a crimp and a wireelement extending from the crimp and the wire element having a strainrelief portion extending distal of the crimp to form a bend extendingsubstantially below a plane defined by the crimp. The tissue shapingdevice may also have an expandable distal anchor, with the distal anchorcomprising a crimp and a wire element extending from the crimp and thewire element having a strain relief portion extending distal of thecrimp to form a bend extending substantially below a plane defined bythe crimp. The tissue shaping device may also have a connector extendingbetween the proximal anchor crimp and the distal anchor connector crimp.

In some embodiments, the proximal anchor wire element further includes avessel engagement portion extending proximally from the strain reliefportion and away from the crimp, a vessel engagement portion extendingproximally from the strain relief portion and away from the crimp, aproximal anchor lock adapted to lock the proximal anchor in an expandedconfiguration, and/or a distal anchor lock adapted to lock the distalanchor in an expanded configuration.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic view of a human heart with the atria removed.

FIG. 2 is a schematic view of a human heart showing the deployment of atissue shaping device in the coronary sinus.

FIG. 3 is a perspective view of a tissue shaping device according to oneembodiment of this invention.

FIG. 4 is another perspective view of the tissue shaping device of FIG.3.

FIG. 5 is side elevational view of the tissue shaping device of FIGS. 3and 4.

FIG. 6 is a perspective view showing the device of FIG. 3 in anunexpanded configuration and in a partially expanded configuration.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a superior view of a heart 100 with the atria removed. Aspictured, the heart comprises several valves including mitral valve 102,pulmonary valve 104, aortic valve 106 and tricuspid valve 108. Mitralvalve 102 includes anterior cusp 110, posterior cusp 112 and annulus114. Annulus 114 encircles cusps 110 and 112 and functions to maintaintheir respective spacing to ensure complete mitral valve closure duringleft ventricular contractions of the heart 100. As illustrated, coronarysinus 116 partially encircles mitral valve 102 and is adjacent to mitralvalve annulus 114. Coronary sinus 116 is part of the venous system ofheart 100 and extends along the AV groove between the left atrium andthe left ventricle. This places coronary sinus 116 essentially withinthe same plane as mitral valve annulus 114, making coronary sinus 116available for placement of shaping device 200 in order to effect mitralvalve geometry and to restore proper valve function.

FIG. 2 illustrates one possible embodiment of an implantable shapingdevice 200, which is deployable in coronary sinus 116 or other bodylumen. As illustrated in FIG. 2, device 200 generally comprises anelongated connector 220 disposed between a distal anchor 240 and aproximal anchor 260. Both distal anchor 240 and proximal anchor 260 areshown in their deployed (i.e. expanded) configuration in FIG. 2,securely positioned within the coronary sinus 116. FIG. 2 furtherdepicts, in phantom, a deployment system 300 comprising catheter 302 fordelivering and positioning shaping device 200 in the coronary sinus 116.Further details of the delivery system may be found in U.S. applicationSer. Nos. 10/946,332 and 10/945,855.

FIGS. 3-5 show one embodiment of a tissue shaping device 400 withproximal anchor 402 and distal anchor 404 in their expanded and lockedconfigurations. In this embodiment, proximal anchor 402 is made from ashape memory metal wire (such as Nitinol) extending from a crimp 406.Stress relief portions 408 of the wire extend distal to crimp 406; thepurpose of these stress relief features will be discussed below withreference to FIG. 6. The wire extends upward from stress relief portions408 to form vessel engagement portions 410 which cross to form a FIG. 8pattern, as shown. Vessel engagement portions 410 and crimp 406 engagethe inner wall of the coronary sinus or other vessel in which the deviceis implanted. The wire also forms a lock loop 412 which interacts withan arrowhead-shaped element 414 extending from the proximal end of thecrimp to form the proximal anchor lock. Actuation of the proximal anchorlock is described in U.S. application Ser. Nos. 10/946,332 and10/945,855.

Likewise, distal anchor is made from a shape memory wire 416 extendingfrom a crimp 418. Stress relief portions 420 of the wire extend distalto crimp 418. Wire 416 extends upward from stress relief portions 420 toform vessel engagement portions 422 which cross to form a FIG. 8pattern, as shown. Vessel engagement portions 422 and crimp 418 engagethe inner wall of the coronary sinus or other vessel in which the deviceis implanted. Wire 416 also forms a lock loop 424.

Extending between anchors 402 and 404 are a substantially flat connector426 and a wire connector 428. In this embodiment, connectors 426 and 428are both made of shape memory metal, such as Nitinol. When device 400 isdeployed within the coronary sinus or other vessel, the distal anchor404 is deployed from the delivery catheter first, then expanded andlocked to maintain its position within the vessel. A proximal cinchingforce is then applied on the distal anchor from, e.g., a tether attachedto arrowhead element 414 until an appropriate amount of reshaping of themitral valve or other tissue has occurred (as determined, e.g., byviewing blood flow with fluoroscopy, ultrasound, etc.). Whilemaintaining the cinching force, proximal anchor 402 is deployed from thedelivery catheter, expanded and locked in the expanded configuration.The device 400 may then be released from the delivery system's tether.By spanning the distance between proximal anchor 402 and distal anchor404, connectors 426 and 428 maintain the reshaping force on the tissue.

When deployed in the coronary sinus to reshape the mitral valve annulus,the tissue shaping devices of this invention are subjected to cyclicbending and tensile loading as the patient's heart beats. Device 400differs from prior tissue shaping devices by changing thecross-sectional profile of the connector, in this illustration by makingconnector 426 substantially flat. This shape provides improved fatigueresistance over prior devices whose wire connectors had a round profile.In addition, the flat shape of connector 426 helps device 400 to orientitself within the vessel during the deployment process. In alternativeembodiments, connector 426 may have a more round shape, with, e.g., anoval cross-section or other non-circular cross-section instead of arectangular cross-section.

Prior to use, tissue shaping devices such as those shown in FIGS. 3-5may be stored in cartridges or other containers, such as described inU.S. application Ser. Nos. 10/946,332 and 10/945,855, then delivered tothe coronary sinus or other vessel in a delivery catheter, as shown inFIG. 2. During storage and delivery, the device may be compressed in thedirections shown by the arrows in FIG. 6 from an unstressed expandedshape into an unexpanded configuration, such as the configuration shownin phantom in FIG. 6. There are two aspects of stresses experienced bythe device. In one aspect stress may be imparted while the device iscollapsed for storage and delivery. While collapsed it is possible thatthe change of shape from unstressed configuration to collapsed conditioncreates an area of higher stress. Anchor wire forms are designed withstress reliving element (420) to reduce this type of stress on implantwhile in storage or during deployment. Another aspect of stress onimplant happens when it is deployed, locked, and detached from thedelivery catheter. This type of stress comes from the repeated motion(fatigue) of heart increasing bending stress on implant. This couldresult in implant fracture. The connector element design (426) with flatribbon provides resistance to this bending stress thus reducing chancesof fatigue fracture. In this embodiment, therefore, the device isprovided with stress relief features. Bent portions 408 of the proximalanchor wire provide extra stress relief while the device is in storageand relieves material stress on the wire that would otherwise be presentwhere the wire emerges from crimp 406. Similar stress relief bends 420in distal anchor wire 416 serve a similar function.

FIG. 6 shows device 400 in a compressed storage configuration (shown inphantom) and in a partially expanded but not yet locked configuration.After emerging from the delivery catheter, the shape memorycharacteristics of anchors 402 and 404 will cause them to expand to,e.g., the configuration shown in solid line in FIG. 6. After the userconfirms that the device is in the desired position, the user may thenemploy the device delivery system (such as that described in U.S.application Ser. Nos. 10/946,332 and 10/945,855) to lock the distalanchor by moving lock loop 424 distally with respect to the connector.Distal movement of lock loop 424 beyond the position shown in FIG. 6will cause bent portions 430 and 432 of connectors 426 and 428,respectively, to move toward each other, permitting lock loop to passover them to the position shown in FIG. 1, thereby locking the distalanchor in an expanded configuration. After placement of the proximalanchor in its desired position (after, e.g., application of a proximallydirected cinching force), proximal anchor lock loop 412 may be advanceddistally over arrowhead element 414 to lock the proximal anchor in anexpanded configuration.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method of modifying the geometry of a mitralvalve, comprising delivering a tissue shaping device to a coronarysinus; deploying a distal anchor from a delivery device and into thecoronary sinus to allow the expandable distal anchor to expand; lockingthe distal anchor in a locked configuration; applying a proximalcinching force to the distal anchor to reshape tissue; while maintainingthe proximal cinching force, deploying the proximal anchor from thedelivery device to allow the proximal anchor to expand.
 2. The method ofclaim 1 further comprising locking the proximal anchor in a lockedconfiguration after allowing the proximal anchor to expand.
 3. A tissueshaping device adapted to be disposed in a vessel near a patient's heartto reshape the patient's heart, the tissue shaping device comprising: anexpandable proximal anchor; a proximal anchor lock adapted to lock theproximal anchor in an expanded configuration; an expandable distalanchor; a distal anchor lock adapted to lock the distal anchor in anexpanded configuration; and a connector disposed between the proximalanchor and the distal anchor, the connector having a substantiallynon-circular cross-section, wherein the distal anchor lock comprises abend in the connector.
 4. The device of claim 3 wherein the distalanchor lock further comprises a compliant element adjacent the bend inthe connector, the compliant element being adapted to change shapeduring a distal anchor locking operation.
 5. A tissue shaping deviceadapted to be disposed in a vessel near a patient's heart to reshape thepatient's heart, the tissue shaping device comprising: an expandableproximal anchor; a proximal anchor lock adapted to lock the proximalanchor in an expanded configuration; an expandable distal anchor; adistal anchor lock adapted to lock the distal anchor in an expandedconfiguration; and a connector disposed between the proximal anchor andthe distal anchor, the connector having a substantially non-circularcross-section, wherein the connector comprises a first connector, thedevice further comprising a second connector extending between theproximal and distal anchors.
 6. The device of claim 5 wherein the distalanchor lock comprises at least part of the second connector.